//给定二叉搜索树的根结点 root，返回值位于范围 [low, high] 之间的所有结点的值的和。 
//
// 
//
// 示例 1： 
// 
// 
//输入：root = [10,5,15,3,7,null,18], low = 7, high = 15
//输出：32
// 
//
// 示例 2： 
// 
// 
//输入：root = [10,5,15,3,7,13,18,1,null,6], low = 6, high = 10
//输出：23
// 
//
// 
//
// 提示： 
//
// 
// 树中节点数目在范围 [1, 2 * 10⁴] 内 
// 1 <= Node.val <= 10⁵ 
// 1 <= low <= high <= 10⁵ 
// 所有 Node.val 互不相同 
// 
//
// Related Topics 树 深度优先搜索 二叉搜索树 二叉树 👍 356 👎 0


package com.tyrone.leetcode.editor.cn;

public class RangeSumOfBst {
    public static void main(String[] args) {
        Solution solution = new RangeSumOfBst().new Solution();
    }
    //leetcode submit region begin(Prohibit modification and deletion)

    /**
     * Definition for a binary tree node.
     * public class TreeNode {
     * int val;
     * TreeNode left;
     * TreeNode right;
     * TreeNode() {}
     * TreeNode(int val) { this.val = val; }
     * TreeNode(int val, TreeNode left, TreeNode right) {
     * this.val = val;
     * this.left = left;
     * this.right = right;
     * }
     * }
     */
    class Solution {
        int sum = 0;
        public int rangeSumBST(TreeNode root, int low, int high) {
            dfs(root, low, high);
            return sum;
        }

        private void dfs(TreeNode root, int low, int high) {
            if (root == null) return;
            if (low <= root.val && root.val <= high){
                sum += root.val;
            }
            if (low<=root.val)
                dfs(root.left,low,high);
            if (high>=root.val)
                dfs(root.right,low,high);
        }


    }

    //leetcode submit region end(Prohibit modification and deletion)
    public class TreeNode {
        int val;
        TreeNode left;
        TreeNode right;

        TreeNode() {
        }

        TreeNode(int val) {
            this.val = val;
        }

        TreeNode(int val, TreeNode left, TreeNode right) {
            this.val = val;
            this.left = left;
            this.right = right;
        }
    }
}